Bonfire night

04/11/11

What is inside a firework?

Bang! Oooh! Aaah! Amazing! Fireworks are one of life’s great simple pleasures and never fail to dazzle on bonfire night. So how do these little paper rockets fly so high up in the sky, exploding with booming noises and sparkling colours? Are they full of lemon sherbet, space dust and popping candy? Or is each one a shooting star caught out of the sky?

It will come as no surprise that the answers behind the magic of fireworks can be found in scientific explanation. There are lots of complicated ingredients in a firework and most of them can be found in the big Table of Elements:

Fireworks contain a dry powder concoction made from a mixture of chemicals, metals and other clever substances. When set alight, these powders react in different ways. The big bangs and whistles you hear come from flash powder (a chemical that was used to create the flash for photography during the 1800s but still used on lots of film sets today). Flash powder is a combination of fuel-like metal and a chemical that provides oxygen to ignite the fuel. Add a little bit of bismuth trioxide and you get that distinct, crackling sound. Throw some food preservatives and vaseline into the mix and you can get an ear-splitting whistle.

The colour of the firework depends on the mixture of metals in the powder. Copper produces blue sparks, barium creates green, calcium will burn orange and strontium carbonate will explode bright red! There is a whole host of different metals that can be used in fireworks to create all those beautiful colours. Fireworks might seem like magic, but they’re really closer to alchemy, made from special and carefully made mixtures cooked up by chemists in their labs!